Adsorption and reactions of propenoic acid and 2-fluoropropanoic acid on Cu(100) and O/Cu(100)

Hong Ping Lin, Zi Xian Yang, Szu Han Lee, Tai You Chen, You Jyun Chen, Yun Hsien Chen, Guan Jie Chen, Sheng Xun Zhan, Jong Liang Lin

Research output: Contribution to journalArticlepeer-review

Abstract

X-ray photoelectron spectroscopy, reflection-absorption infrared spectroscopy, and temperature-programmed reaction/desorption have been employed to investigate the adsorption and reaction pathways of CH 2 =CHCOOH and CH 3 CHFCOOH on Cu(100) and oxygen-precovered Cu(100) [O/Cu(100)]. In the case of CH 2 =CHCOOH on O/Cu(100), CH 2 =CHCOO is the surface intermediate detected between 110 K and 400 K. CH 2 =CHCOO is adsorbed vertically and can change adsorption sites at a higher temperature. The propenoate (acrylate) decomposes at higher temperatures (>500 K), with formation of >C=C=O (ketenylidene) surface species and gaseous products. On Cu(100), CH 2 =CHCOOH is adsorbed in dimer form and can dissociate to generate CH 2 =CHCOO and CH 3 CHCOO intermediates on the surface. The CH 3 CHCOO continuously recombines with the H from deprotonation of CH 2 =CHCOOH, resulting in the formation CH 3 CH 2 COO. The co-existing CH 2 =CHCOO and CH 3 CH 2 COO further decompose at ∼550 K to evolve reaction products, but without >C=C=O being detected. On O/Cu(100), CH 3 CHFCOOH readily deprotonates to form CH 3 CHFCOO at 120 K. This intermediate reacts on the surface at ∼460 K to evolve gaseous products, also producing CH 2 =CHCOO. In the case of Cu(100), deprotonation of CH 3 CHFCOOH occurs at ∼250 K, forming CH 3 CHFCOO. Without oxygen on the surface, this intermediate decomposes into HF and CH 2 =CHCOO at ∼455 K.

Original languageEnglish
Article number164703
JournalJournal of Chemical Physics
Volume150
Issue number16
DOIs
Publication statusPublished - 2019 Apr 28

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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